Rock drill



May 17, 1927.

F. M. SLATER ROCK DRILL iNVENTOR fiedjiaiafeh Filed June 24, 1925 Hi5 ATTORNE Patented May 17., 1927.

UNITED STATES PATENT OFFICE.

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ROCK DRILL.

Application filed June 24, 1925. Serial No. 38,165.

This invention relates to fluid actuated rockdrills of the hammer type, but more particularly to valves for drills of said type in which automatic rifle bar rotation 15 provided for the drill steel.

The objects of the invention are to enable the inlet to the cylinder to be controlled by a sleeve valve encircling the rifle bar while the exhaust from the cylinder is controlled by a separate valve governed by the movement of the piston. Further objects of the invention will hereinafter appear and the invention is shown in its preferred forms -in the accompanying drawings, in which Figure 1 is a longitudinal sectional elevation of a rock drill partly broken away embod ing the invention,

Figure 2 is a similar view showing the parts in a difierent position, and

Figure 3 is a sectional detail view of a modification of the valve.

The invention is shown applied to a hand held rock drill for purposes of illustration.

Referring to the drawings, the cylinder A is provided with the reciprocating hammer piston B having the fluted forward extension or shank C imparting blows of impact to the drill steel D. The rifle bar E'has the rotation ratchet F and ratchet ring G as usual. A handle 11 is provided for the machine and the parts are. heldtogether by the usual side bolts, not shown. Y

The back head J is provided with the inlet K for ressure fluid entering the chamber L having the passages O and P controlled by the inlet valveQ.

This valve is inthe form of a sleeve having the central enlarged head R and thereduced and faces S and T. Passages U and V lead tively from the valve chamber to the rearward and forward ends of the cylinder. The central head It of'the valve operates in achamber W n to atmosphere through the ort X. 1 ckerv rts Y and Z in the cylin er communicate ypassages a and b with the chamber W at each side of the valve head R.

The cylinder is provided with the exhaust valve easin 0 containing the exhaustvalve d having t 0 end heads 0 and f controlling the ports 9 and h in the cylinder, so that the cylinder may be exhausted through the valve casing to the atmospheric ports 5. Small ports I: and 0 connect the ends of; the cylinof the cylinder and thevalve (i will be held 5' der with the, ends of the valve casing c for throwing the exhaust valve d in one direction or the other. a

The inlet valve Q preferably slides on a sleeve p surrounding the rifle bar E which sleeve is ti htly sealed, as shown in the back head J an back bushing J, but if desired.

the sleeve 1) and the valve Q may be formed in one piece as indicated in Figure 3 at q.

The operation of the device is-as follows: Assuming that the. piston and valves are in the position indicated in Fi re 1, the pis. ton will be moving on its orward stroke. Live pressure fluid is supplied at the inlet K to the chamber L and passes through the passages P and U around-the valve to the rearward end of the cylinder to drive thevalve Q and throws said valveforwardly to admit ressure fluid through the passa es 0 and to the forward end of the cylin er Asfor driving the piston rearwardly as indi cated in Figure 2. When the piston B has I covered theexhaust port it at the forward end. of the cylinder, the compression due .to'

the forward movement of the piston and also live pressure fluid acting 'throu h the port 0 will cause the. exhaust valve the mg the exhaust port g from the rearward end to moveto in its rearward position by live pressure fluid.

On the return or rearward strokeof the piston, the 'valve Q is-thrown rearwardly when the kicker port Z is uncovered by the piston and the exhaust valve d is'thrown forwardly due to pressure through the small poi'tg: and the cycle is indefinitely repeated. c

.1. In a fluid actuated rock drill of the hammer type, the combination of a cylinder 105 and reciprocating piston, rotation mechanism forthe drill steel including a riflejbar,

a valve in the form of a sleeve. surrounding the rifle bar for controlling the admission f P su u to h ends of the cylinposition indicated in Figure 2, thus open- I ling de'r, a valve casing located 'at the side of the cylinder having exhaust ports leading locate in the'said valve casing for controlthe exhaust of motive fluid from the cylinder through the said exhaust ports and valve casin to atmosphere.

2. .In a uid actuated'rock drill of the hammer type, the combination of a cylinder and reciprocating piston, .a back head for the cylinder and a riflebar passing through said back head .and 000 crating with t e piston, a sleeve surroun ing said rifle. bar tightly sealed in the b ck head, a valve chamber in the back head, an inlet valve in said valve chambersurro'unding the rifle bar sleeve and slidable thereon for controlling the alternate admission of pressure fluid to each end of thecylinder a cylindrical valve chamber at the side of the cylinder, exhaust ports leading from each end of the cylinder to the ends, of the said valve chamber, a port leading to atmosphere located in the chamber and to control the said exhaust ports leadin from the cylinder.

'3; In a uid actuated rock drill of the hammer type, the combination of a cylinder and reciprocating "piston, rotation mecha? nism for the drill steel including a rifle bar,

exhaust means for the c linder overrun by the piston at each and o its stroke, a valve chamber located at the rearward end of the rock drill coaxial with the longitudinal axis of the-cylinder, a stationary sleeve surrounding the riflebar and sealing the valve cham her from the cylinder, and an inletvalve in said chamber surrounding and sliding on said sleeve, said inlet valvecontrolling'only the admission of pressure fluid to both ends of the cylinder. i

In testimony whereof I have signed this specification.

v FRED M. T R. 

